Ealse twist device



June 9, 1964 J. H. SEARLES FALSE TWIST DEVICE Filed Feb. 11, 196 3 //VVENTOR JOHN H. SEARLE'S WWW Wm A rm rney United States Patent C 3,136,110 EALSE TWIST DEVICE .ioim Ii. Scarlcs, Pittsburgh, Pa., assignor to Pittsburgh Plate Glass Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 11, 1963, Ser. No. 257,531 2 Claims. (Cl. 5777.45)

This invention relates to an improved false twist device and more particularly to a false twist device for use with yarns having a low abrasion resistance.

This invention has particular utility in the continuous crimping of fiber glass yarns. In copending patent application Serial No. 246,889, filed December 26, 1962, and entitled Fibrous Product and Process of Making the Same" there is disclosed a process for continuously crimping a tow of fiber glass strands. In this process a number of glass filaments or fibers are formed into a strand. A plurality of strands are gathered as a tow and the tow is pulled through a furnace or heater and then a false twist device. The false twist device imparts a twist in one direction to the portion of the tow in the furnace so that the glass fibers are deformed by heat into a twisted configuration. The false twist device untwists the tow after the fibers have cooled sufficiently to a permanently crimped shape. As discussed in the above enumerated application, the individual filaments or fibers are eated with an organic lubricant and binder before they are gathered into a strand. The binder bonds the fibers together and the lubricant improves the abrasion resistance of the strands so that the strands do not abrade as they contact other surfaces in winding and use.

In the crimping process the fiber glass strands in the tow must be heated to a sufiiciently high temperature to soften the glass fibers. At this high temperature both the binder and the lubricant thermally decompose and the fibers lose the abrasion resistance previously supplied by the lubricant. The crimped strands of fiber glass are, therefore. easily abraded and special care must be exercised in handling the crimped tow after it leaves the furnace.

Apparatus for mechanically applying a false twist to a running yarn are known. For example, US. Patent #2,813,393, issued November 19, 1957, to Kingsbury et al., discioses a false twist spindle that is useful with yarn having high abrasion resistance. This disclosed spindle is not, however, suitable for use with yarns having a low abrasion resistance such as the thermally treated fiber glass tow previously described. The false twist spindle disclosed in the above patent includes a coupling block that has an axial bore and an offset horizontal bore. The yarn isthreaded first through the axial bore of the coupling block. then across the top of the coupling block, down one side of the coupling block, through the offset horizontal bore and then up the other side of the coupling block. With this structure the yarn is looped about the coupling block and is required to reverse its direction of travel and make several sharp turns as it passes through the false twister. With a yarn having a low abrasion resistance, the tortuous path followed by the yarn would severely abrade the yarn and under certain conditions cause breakage and parting of the yarn.

Briefly. the present invention provides an improved false twist spindle wherein a substantially lineal passageway is provided for the yarn. The false twist spindle is free of sharp corners and minimizes the abrasion experienced by the yarn as a false twist is imparted thereto.

Accordingly, the principal object of this invention is to provide a false twist spindle that may be used with yarns having a low abrasion resistance.

Another object of this invention is to provide a false twist spindle that does not require the yarn to follow 52. tubular body portion 24 with the shoulder portion 50 3,136,110 Patented June 9, 1964 "ice a tortuous path or to reverse its direction of travel as the yarn passes therethrough. I

These and other objects and advantages of this invention will be more completely described and distinctly pointed out in the following specification, the accompanying drawings and the appended claims.

In the drawings:

FIGURE 1 is a schematic representation of a process for preparing crimped yarn from continuous strands of fiber glass and illustrating the improved false twist spindle.

FIGURE 2 is a sectional view in side elevation of the false twist spindle.

FIGURE 3 is a front view of the false twist spindle illustrated in FIGURE 2.

In FIGURE 1 the process for crimping a fiber glass yarn is schematically represented. A plurality of untwisted fiber glass strands 10 are drawn from a suitable source and are gathered into a tow 12. The tow 12 is pulled through a furnace 14 and a false twist device generally designated by the numeral 16 by means of the pulling force exerted by the take-up roll 18. Suitable pulleys, tension control mechanisms, twist stopping devices and the like are provided to control the tow 12 during the process. A motor 20, schematically illustrated in FIG- URE 1, is arranged to drive a friction wheel 22 at a preselected speed. The friction wheel 22 in turn rotates the spindle portion of the false twister 16.

The detailed construction of the false twister 16 is illustrated in FIGURES 2 and 3. The false twister 16 has a tubular body portion 24 with external annular flange portions 26 and 28. The body portion 24 is arranged to be rigidly secured to a support or standard and remains in a fixed position.

The body portion 24 has an axial bore or passageway 30 with spaced internal shoulders 32 and 34. The passageway 30 has a pair of annular recessed portions 36 and 38. Bearings 40 and 42 are positioned in the bore 30 in abutting relation with the respective shoulders 32 and 34 and snap rings 44 and 46 are positioned in the recessed portions 36 and 38 to maintain the bearings 40 and 42 in fixed position within the body portion bore 30. Snap ring 44 is of bowed construction and serves as a spring to take up tolerances and to urge bearing 40 against the shoulder 34. The bearings 40 and 42 are preferably of the type that are operable to rotate at high speeds, for example between 75,000 r.p.m. and 150,000 r.p.m. and include suitable dust seals.

A tubular spindle 48 has an external intermediate shoulder portion 50 and an outwardly flared end portion The spindle 48 is positioned coaxia'lly within the abutting the inner race of bearing 42. The inner races of bearings 40 and 42 are lightly press fitted onto the spindle 48 so that the spindle 48 is freely rotatable relative to the body portion 24.

The spindle 48 has an internal axial passageway or bore 54 that tapers outwardly with the flared end portion 52. Adjacent the spindle end wall 56 the passageway 54 has an internally threaded portion 58 which terminates at an inturned shoulder 60. An insert generally designated by the numeral 62 (FIG. 3) is threadably secured in the bore 54 and abuts the inturned shoulder portion 60. A pair of annular discs 64 and 66 are suitably secured to the spindle 48 for rotation therewith. The discs 64 and 66 serve as an aerodynamic seal and shield the body portion inner passageway 30 from dust or other foreign material.

The insert 62 is disc-like in shape and has a peripheral threaded portion that mates with the thread 58 in the spindle bore 54. When assembled the insert 62 is threadably secured within the spindle bore 54 so that the insert 62 rotates with the spindle 48. The insert 62 has four radially extending slots 68, 70, 72 and 74 which have substantially the same dimensions and are symmetrically disposed so that both the insert 62 and the spindle 48 are symmetrically balanced. The slots 6874 have rounded or beveled edges 76 and 78 (FIG. 2) to provide a smooth surface for the tow of fibrous material and minimize abrasion during the twisting operation. The slots 68-74 have a radial end wall 80.against which the tow 12 rides as it is drawn through the spindle passageway 54 as later explained. The end wall 80 is radially spaced from the longitudinal axis of the spindle 48. The inner spindle bore 54 preferably has a highly polished surface so that the tow of fibrous material will not snag or abrade therein.

Although an insert having four slots has been illus trated, it should be understood that fewer slots may be employed. It is preferred, however, that the slots be arranged symmetrically on the insert to provide a balanced device. The friction wheel 22 illustrated in FIG- URE l as being driven by motor 20 frictionally engages the outer wall of spindle 48 and is arranged to rotate the spindle 48 at a preselected speed.

Operation The false twist device generally indicated by the numeral 16 provides a false twist for the tow 12 in the following manner. The tow 12 is threaded through one of the radial slots 68-74 in the insert 62 and then through the bore 54 of spindle 48. The spindle 48 is rotated at a high rate of speed by the motor 20 through the friction wheel 22. A centrifugal force is exerted on the tow 12 and it is urged against the peripheral end wall 80 of the slot as is illustrated in FIGURE 3. The portion of the tow passing through the insert 62 is continually urged against the slot radial end wall 80 and as the spindle 48 rotates a twist is imparted thereto. The twisting of the tow 12 is caused by the radial displacement of the tow 12 relative to the axis of the spindle 48 and the axial rotation of the spindle. A limited amount of slippage between the tow 12 and the spindle 48 causes less twist to the tow 12 than the spindle speed would indicate. It has been determined, however, that a sufficient twist is imparted to the tow 12 to deform the fiber glass strands into helical shapes by the apparatus illustrated in FIGURE 1 and the false twist device illustrated in FIGURES 2 and 3.

It will be readily apparent by viewing FIGURE 2 that the tow 12 as it passes through the false twist device 16 does not follow a tortuous path nor is the tow looped about a portion of the false twist device 16. The tow 12 follows a substantially linear path through the internal bore 54 of the spindle 48 and is displaced laterally only at the slotted insert 62. The lateral deflection, however, provides a smooth curvature to the tow 12 and abrasion of the tow by subjecting it to a false twist is minimized. It is believed that the tow 12 under the centrifugal force exerted thereon while the spindle 48 is rotating tends to balloon or bow slightly adjacent the insert 62 so that the tow 12 abuts the inner wall of bore 54 as is indicated in FIGURE 2.

According to the provisions of the patent statutes, the principle, preferred construction and mode of operation of the invention have been explained, and what is com sidered to be its best embodiment has been illustrated and described. It should be understood, however, that, within the scope of the appended claims the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A false twist device adapted to impart a twist to a tow of yarn continuously drawn therethrough comprising,

a body portion having an axial bore,

a tubular spindle having an axial passageway therethrough,

said spindle having an outwardly flared end portion terminating in an annular end wall,

said tubular spindle being axially positioned within said body portion axial bore with said flared end portion extending outwardly therefrom,

bearing means ro-tatably supporting said tubular spindle within said body portion,

said spindle passageway having an annular inturned shoulder portion adjacent said annular end wall,

a disc shaped insert positioned within said spindle passageway in abutting relation with said annular inturned shoulder portion in rotatable relation with said spindle,

said insert having an aperture therein spaced laterally from the longitudinal axis of said spindle,

drive means in frictional engagement with said spindle end portion and arranged to rotate said spindle relative to said body portion,

said spindle adapted to have a tow of yarn pass through said aperture in said insert and through said spindle axial passageway, and upon rotation of said spindle to impart a twist to the tow.

2. A false twist device adapted to impart a twist to a tow of yarn continuously drawn therethrough comprising,

a body portion having an axial bore,

a tubular spindle having an axial passageway therethrough,

said spindle having an outwardly flared end portion terminating in an annular end wall,

said tubular spindle being axially positioned within said body portion axial bore with said flared end portion extending outwardly therefrom,

bearing means rotatably supporting said tubular spindle within said body portion,

said spindle passageway having an inturned shoulder portion adjacent said annular end wall,

a disc shaped insert positioned in said spindle passageway in abutting relation with said inturned shoulder portion and adjacent said annular end wall,

said insert being rotatable with said spindle, said insert having a plurality of radially extending slots arranged symmetrically in said insert,

said slots having peripheral end walls,

said spindle adapted to have a tow of yarn pass through one of said slots in said insert and through said axial passageway,

said spindle operable upon rotation thereof to urge said tow radially outwardly in said slot against the peripheral end wall of said slot and thereby impart a twist to the tow of yarn.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A FALSE TWIST DEVICE ADAPTED TO IMPART A TWIST TO A TOW OF YARN CONTINUOUSLY DRAWN THERETHROUGH COMPRISING, A BODY PORTION HAVING AN AXIAL BORE, A TUBULAR SPINDLE HAVING AN AXIAL PASASAGEWAY THERETHROUGH, SAID SPINDLE HAVING AN OUTWARDLY FLARED END PORTION TERMINATING IN AN ANNULAR END WALL, SAID TUBULAR SPINDLE BEING AXIALLY POSITONED WITHIN SAID BODY PORTION AXIAL BORE WITH SAID FLARED END PORTION EXTENDING OUTWARDLY THEREFROM, BEARING MEANS ROTATABLY SUPPORTING SAID TUBULAR SPINDLE WITHIN SAID BODY PORTION, SAID SPINDLE PASSAGEWAY HAVING AN ANNULAR INTURNED SHOULDER PORTION ADJACENT SAID ANNULAR END WALL, A DISC SHAPED INSERT POSITIONED WITHIN SAID SPINDLE PASSAGEWAY IN ABUTTING RELATION WITH SAID ANNULAR INTURNED SHOULDER PORTION IN ROTATABLE RELATION WITH SAID SPINDLE, SAID INSERT HAVING AN APERTURE THEREIN SPACED LATERALLY FROM THE LONGITUDINAL AXIS OF SAID SPINDLE, DRIVE MEANS IN FRICTIONAL ENGAGEMENT WIOTH SAID SPINDLE END PORTION AND ARRANGED TO ROTATE SAID SPINDLE RELATIVE TO SAID BODY PORTION, SAID SPINDLE ADAPTED TO HAVE A TWO OF YARN PASS THROUGH SAID APERTURE IN SAID INSERT AND THROUGH SAID SPINDLE AXIAL PASSAGEWAY, AND UPON ROTATION OF SAID SPINDLE TO IMPART A TWIST TO THE TOW. 